1. Field of the Invention
The present invention relates to a zoom lens and an imaging apparatus appropriately used particularly for electronic cameras, such as video cameras and digital still cameras, and film cameras. Specifically, the invention relates to the technical field of the zoom lens and imaging apparatus capable of optically correcting the image blur caused by hand shake at the time of photography and achieving miniaturization and high zoom power.
2. Description of the Related Art
Recently, the imaging apparatuses such as video cameras and digital cameras using a solid-state imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor) have come into widespread use.
As the imaging apparatuses have spread, the demand for high image quality has increased. In particular, there is demand for photographic lenses, particularly, zoom lenses, which have an excellent imaging performance, adapted to the solid-state imaging devices having a large number of pixels. Further, the demand for the miniaturization of the imaging apparatus is also strong, and there is the demand for the small-sized and high-performance zoom lens. Moreover, the demand for the high zoom power is also strong, and the image blur as an adverse effect of a high-zoom-power configuration may occur at the time of photography. For this reason, the demand for the high-power zoom lens having a hand shake correction function has been strong.
In the zoom lens disclosed in JP-A-2005-181635, miniaturization is achieved in a way that the prism deflecting the optical path is disposed in the optical system. In addition, the zoom ratio of four times or more is achieved by adopting a lens configuration having four variable power groups.
Likewise, in the zoom lens disclosed in JP-A-2006-71993, miniaturization in the direction of the optical axis is achieved in such a way that the prism is disposed in the optical system.
In the zoom lenses disclosed in JP-A-2005-181635 and JP-A-2006-71993, in order to increase a zoom power, it is necessary to significantly increase the sizes of the lens (the front lens) and the prism arranged to be closest to the object side of the first lens group. For this reason, it is difficult to achieve miniaturization.
Further, in the zoom lens disclosed in JP-A-2005-181635, the zoom ratio of four times or more is achieved. In the lens configuration having four variable power groups, the sixth lens group is further provided, thereby correcting aberrations. Accordingly, a problem arises in that it is difficult to shorten the entire length of the optical system.
Moreover, in the zoom lens disclosed in JP-A-2005-181635, in order to further increase a zoom power, it is necessary to increase shift amounts of the second lens group and the fourth lens group. For this reason, it is difficult to achieve miniaturization in the direction of the optical axis.
In addition, in the zoom lens disclosed in JP-A-2006-71993, the zoom ratio is small, about three times, or so is achieved and it is difficult to satisfy the demand for high zoom power.
Thus, it is desirable to provide a zoom lens and an imaging apparatus securing the favorable hand shake correction function and achieving miniaturization and a high zoom power.